Plasma Vasopressin in Uncontrolled Diabetes Mellitus

Abstract

Concentrations of the antidiuretic hormone, arginine vasopressin, were measured in 28 patients with severe hyperglycemia to determine if abnormalities in hormonal regulation of water excretion could contribute to the extreme dehydration of uncontrolled diabetes mellitus. Vasopressin levels were markedly elevated in both nonketotic and ketotic patients, indicating that vasopressin deficiency plays no role in the polyuria that accompanies hyperglycemia. Instead, the observed increases in vasopressin represent an ineffective effort to conserve water in the face of an overwhelming solute diuresis caused by the glucosuria. The reasons for such marked elevations in plasma vasopressin in these diabetic patients are multifactorial. Both groups of diabetic patients had evidence of hypovolemia, which was sufficient in magnitude to stimulate vasopressin release. Furthermore, nausea provided an independent stimulus to vasopressin secretion in many patients. Osmotic stimulation might have resulted from the large fraction of unidentified plasma solutes, but this factor alone was not sufficient to explain the markedly increased concentrations of vasopressin. Whether such elevations in vasopressin could have metabolic and/or hemodynamic effects in uncrontrolled diabetes remains to be established.

Streptozotocin diabetic rats are hypertensive despite reduced hypothalamic responsiveness.

“…Increased amounts of circulating vasopressin could cause receptor saturation and thereby explain why pressor responses to injected vasopressin were reduced (table 4). Even though plasma vasopressin was not measured in the present studies, others have shown that it becomes elevated not only in diabetic patients 35 but also in various forms of experimental hypertension in rats. 3 *- 37 Bradycardia occurs when diabetes is induced in normotensive rats with streptozotocin 8 or in spontaneously hypertensive ones with alloxan.…”

Sex differences in the association between plasma copeptin and incident type 2 diabetes: the Prevention of Renal and Vascular Endstage Disease (PREVEND) study

“…The arginine vasopressin (AVP) stress-adaptation system has been shown to play a role in glucose homeostasis in both experimental and human studies [1,2]. Epidemiological studies investigating the prospective association between plasma AVP levels and risk of type 2 diabetes are scarce.…”

Real and artefactual erythrocyte swelling in hyperglycaemia

“…As a consequence, there is an increase in serum osmolality and sodium. Even if serum sodium does not completely return to normal values, there is usually an accumulation of "unidentified solutes" within total osmolality [13], mostly ketone bodies, to which erythrocytes are largely impermeable. This leads to a reversal of erythrocyte swelling.…”

“…It results from an osmotic intra-to extracellular water shift in response to hyperglycaemia. Most tissue cells are not freely permeable to glucose, i. e. glucose is an osmotically "effective" solute to them [13]. As glucose is osmotically not "effective" to the erythrocyte, a hyperglycaemic patient should have an increased erythrocyte volume in proportion to the degree of hyponatremia.…”